This invention relates to long term storage of frozen and refrigerated food and biological samples, and more particularly to a passive system including a storage container having high thermal efficiency for storage of such materials at low temperatures for extended periods of time for use in conjunction with a manned space station.
The manned space station being developed by the NASA requires both refrigerated and frozen food for supporting and sustaining the crew, and in all probability the life science experimentation mission will require frozen biological samples. Such food and samples will be required to be transported to and from the space station. Other materials to be processed by the crew may also be required to be maintained under refrigerated or frozen conditions. The number of fluid and thermal interfaces which would be required for the low temperature requirements during the various mission phases of the logistics module appear to make the demands of such active refrigeration system interfaces unfeasibly prohibitive for accommodation by the logistics module.
For example, the low temperature requirements would have to be provided by ground support equipment prior to launch, but during ascent and orbit in the shuttle, an interface between the module and the shuttle would be required. Additionally, during transit from the shuttle to the space station, the logistics module itself would be required to provide these requirements without a separate support system. While at the space station an interface between the logistics module and the space station would be required to maintain the low temperature requirements. And finally, during descent and landing, an interface would again be required between the logistics module and the shuttle.
In view of the difficulties, both technological and economic, envisioned for such a large number of active interfaces, a passive system eliminating the fluid/thermal interfaces and associated electrical interfaces appears necessary for mission purposes.